Geely EC715 2009, Workshop Manual

Page: 1998 / 2181

11.17.2 Description and Operation
11.17.2.1 System Working Principle
Overview
This vehicle uses three types data communication:
– CAN Bus
– K Bus
– LIN Bus
CAN Bus Description
– CAN is the Controller Area Network acronym, stands for
Controller Area Network bus, the control devices connected
to each other and exchange data .
CAN bus communication medium is a twisted-pair, in which
high-speed CAN bus communication speed is 500 kbps.
Twisted-pair terminals are two 120 Ω resistors, one end is
in the engine control module (ECM), the other side is in the
body control module (BCM). High-speed CAN bus is a
differential bus. High-speed CAN bus serial data bus (H)
and high-speed CAN bus serial data bus (L) from a
stationary or idle-level drive to the opposite limit. About 2.5
V idle level is considered to transmit data and interpreted
as a hidden logic 1. The extreme limit of line-driven, high-
speed CAN bus serial data bus (H) would increase the 1V
and the high-speed CAN bus serial data bus (L) will reduce
1 V. Limit voltage difference 2 V is considered dominant
transmission of data and explain the logic 0 (as shown).
FE11-1504b
–
If the communication signal is lost, the program will target
the control module losing communication to set DTC codes.
The fault diagnosis codes can be read by scan tool.
Note
Serial data loss does not mean that the module is
faulty.
–
The advantages of CAN bus:
1. Reduce the number of sensors and signal wires.
2. Reduce the number of wires in wiring harness.
3. Greatly reduces the weight of the wire harness.
4. Reduce the number of control devices pins.
5. Improve the reliability and durability.
– In this vehicle, high-speed CAN bus allows BCM, ECM,
ABS, airbag control module, IP Cluster communication.
LIN Bus Description
– LIN is used for automotive distributed electronic control
system and is a new type of low-cost serial communication
system, mainly for smart sensors and actuators serial
communication.
–
LIN bus features:
Based on UART data format
Single-master multi-structural
Single transmission :0-12 V
Communication speed: 19.2 kbps
K Bus Description
– K bus is for communication between the vehicle ECM and
the external test equipment. Transfer rate is 10.47 kbps.
Voltage is between 0 V and 12 V: 12 V, logic "1"; 0 V, logic
"0".
Data Link Connector Description
Datalink connector (DLC) is the result of consultation between
automotive manufacturers and regulations. scan tool must be
used to communicate with the vehicle and for vehicle
communication system programming.
The connector must meet the following conditions:
– Connect all scan tools 16-pin connector.
–
Always use No.16-pin to provide power to scan tool.
– Always use No.4-pin as the scan tool ground.
11-514 Data Communication System Body Electric
EC718/EC718RV EC715/EC715RV 10/2009